Direct-current voltage multiplier



Dec.- 21, 1948. A.-M.' CURTIS DIRECT CURRENT VOLTAGE MULTIIPLIER Filed May 2, 1945 37 as I INVENTOR A. M. CURTIS A fiORA/Ek Patented Dec. 21, 1948 DIRECT-CURRENT VOLTAGE MULTIPLIER Austen M. Curtis, South Orange, N. J., assignor to Bell Telephone Laboratories, Incorporated.

New York, N. Y., a corporation of New York ApplicationMay 2, 1945,-Seria'1 No. 591,487

. 4 .Claims.

This invention relates to direct current voltage multiplying arrangements of the vibrator-condenser type.

An objectof the invention is to provide an improved system for efficiently multiplying an initial 5 voltage to supply an output circuit with a high direct current potential.

A feature of the invention residesin alternately connecting a primary source of direct current to a first condenser and then discharging the first'x condenser in series with the source into-second and third. condensers in parallel which second and third condensers, now charged to substantially twice the initial potential, are-then discharged in series into a succeeding condenser network, or

work circuit, at substantially four times the voltage of the primary source.

Another feature of the invention resides in employing sealed, mercury contact, switches of the general type disclosed in an application filed July.

21, 194.4, in the name of E. T. Burton, SerialNo. 545,985, which switches have the characteristic of passing at their closed contacts a considerably larger currentthan they can open without serious sparking.

A further feature resides in the provision of means for co-ntrolling the wave form of the charging current for said condensers so that the current, at the instant of make and. break of the relay contacts, is a small fraction of. the current required to perform the work of charging the condensers, said means also serving to prevent the charged condensers from losing a portion of their charge, by discharge through a preceding lower potential stage, due to the so-called bridging characteristic of the mercury contact relays'employed.

The invention will be understood from the. following description when read in connection with the accompanying drawing, the single' figure! of which represents the circuit arrangement, of a system for delivering to a work circuit a direct current potential substantially four times that of a primary direct current source.

Referring to the drawing, direct current potential from a source, not shown, is supplied over conductors l and 2. As the circuit functions, under control of continuously vibrating contacts, or circuit closing devices, VI and V2, a source of pulsating current must first be, provided. .This

pulsatin current in the present arrangement is produced by a relay 3 whichcomprises asinglepole, double-throw, mercury contact switch surrounded by a singlejenergizing winding 5.. When potential is applied to conductors land 2, current :fiows from conductor I, for example, over conductor 6, resistance 1, inductance-resistance network 8, Winding 5, contacts 9 and conductor ID to the other supply conductor 2.

With the back contacts 9, of relay 3, closed current builds up through network 8 until it reaches the operating value of relay 3 whereupon armature I I is attracted by magnetic element I2 thereby opening back contacts 9 and closing front con "tacts l3.- The current through winding 5 continues to flow through condenser l4 and resistance 15, after contacts 9 are open and therefore winding 5 remains energized and the contacts l3 are held closed until condenser M has been charged suiiiciently to reduce the current flowing through winding 5 to the release value of the re- I lay whereupon the armature returns to its original position and recloses contacts 9 at which time condenser I4 is discharged in series with resistance I 5 and contacts 9 whereupon the cycle repeats thus alternately closing and opening contacts [3 at a predetermined rate in accordance with the constants of the circuit and the characteristics of armature il. Suitable adjustment ,of theresistance 1 and network 5% is effective to regulate the vibration frequency of armature II.

The periodic closure of contacts 13 of switch 3 causes vibrating switching devices Vi and. V2

'ing.

' to alternately open their back contacts l8, I9, 20 and 2| and to close their front contacts 22, 23, 24

and-25. The circuit for operating device VI including conductors 6 and 2S, winding I6, conductor 21, adjustable resistance 28, contacts I3,

and conductor H1, and the circuit for V2 including conductors 6 3!], adjustable resistance 3!, contacts l3 and conductor l0.

and 29, winding i7, conductor By adjusting resistances 28 and 31 the operating currents for windings I6 and I! can {be controlled. 4c

' On the first operation of devices VI and V2 their front contacts 22, 23, Z l and 25 are closed and contacts l3, i9, 20 and Eli are opened where upon condenser 32 is connected across the supply conductors l and 2 in series with inductance 33 and ohmic resistance 3d of such values that the current in the circuit at the initial closing of the contacts is small thus preventing excessive spark- Condenser 32 receives a chargeat this time substantially equal to the potential connected to conductors l and 2. At the same time condensers v3!: and 36 are connected in a series circuit which can be traced from the upper plate of condenser 35, closed front contact 24 of device V2, condenser 36. front contactsZE, inductance 31, ohmic resistance 38, load resistance 39 in parallel with storage condenser 52, and back to the lower plate of condenser 35. It is assumed, however, that condensers 35 and 36 are at zero potential at this time and therefore there will be no current surge through the load resistance and condenser 52.

When the driving or pulse relay 3 releases for the first time and opens front contacts ill devices V and V2 will deenergiaed to open th ir front contacts 22, 23, ii and and to close their back contacts l8, Ill, and 2i thus disconnecting condenser 32, now charged, from the supply circuit conductos l and 2, and connect ing this condenser (52) in series with the supply source and in parallel with condensers 35 and 36, whereby these two latter condel vrs (35 and 36) each start to receive a charge from the potential stored in condenser 32 plus the potential of the supply source which initially will be somewhat less than twice the potential of the source. The circuit at this time can be traced from the left-hand plate of condenser 32, contacts iii of Vi, inductance 4U, shunted by resistance 4|. resistance 42, condenser 35, supply conductor ll, through the supply potential source to conductor i, inductance 43, ohmic resistance 44, and back contacts ill of Vi to the right hand plate of condenser M The parallel circuit for IJI'I. condenser 36 can be traced from the upper plate of condenser 35, inductance 45, ohmic resistance 46, back contacts 2| of V2, condenser 36, back contacts 28, inductance 41 and ohmic resistance 43, back to the lower plate of condenser 35.

As before mentioned condensers and each initially receive a charge which is somewhat less than twice the potential of the supply f urce, i. e., the potential of initially chai i condenser 32 P e potential of the source. On the next operation of the pulse relay 3, its front contacts again close and drive Vi and V2 to again open their back :ontacts and close thei front contacts thus reconnecting condenser 1" partially discharged, to the supply conductor whereby this relay is reclr' "red to the source of potential.

As the loa contacts of Vi and V? are now open, condensers 35 and 35 are again connected in a circuit including load. resistance 39 and in an aiding direction with respect to the polarities of their respective charges whereby the potential applied across the condenser 52 and load resistance substantially the sum of the potential charges on condensers 35 and 35, i. e., somewhat less than [our times the potential of the supply source.

The circuit for condensers 35, Eli, 52 and load resistance 39 at this stage of the operating cycle can be traced from the upper plate of condenser 35, front contacts 24 of V2, condenser 38, contacts n.5, inductance 31, resistance 38, condenser 52 and load resistance 39 in parallel and back to the lower plate of condenser 35.

The foregoing cycle of operation continues to alternately charge and discharge condensers 32, 35 35 under control of devices Vi and V2 which are, in turn, alternately energized and deenergized due to the pulsating current supplied by relay 3, and, in a short time, i. e., after a few sucoes ve operations of devices V I and V2, con denser 52 builds up a potential across the load which is substantially equal to four times the voltage of the supply source minus a quantity depending upon the losses in the devices, Vi and V2 and the circuit elements.

In the above connection it should be understood that devices VI and V2 may be operated by any other suitable means, in substitution for ill relay 3 as, for example, by rotary interrupter.

Spark killing networks including capacity, inductance and ohmic resistance shunt the respective contacts 18 and 25, inclusive, of devices l V2 to limit the current tliereacross and prevent excessive arcing at the moment of final "ore-air, as for example condenser ll), inductance 5G and ohmic resistance 5i connected in shunt to contacts 22.

Condenser 52, connected in parallel with load resistance 39, serves as a storage reservoir from which the load draws continuous energy as otherwise the load would not receive any input while condensers 35 and 35 were being charged. Condenser 52 also acts as a filter to by-pass and prevent alternating component of the current from appearing in the load circuit.

What is claimed is:

1. In a voltage multiplying system, a source of direct current, a load circuit, a plurality of condensers, and vibratory means for successively changing a first one of said condensers to the potential of said source, discharging it in series witl. said source into second and third condensers in parallel, and then simultaneously recharging said first condenser from said source and discharging said second and third condensers in series into said load circuit.

2. In a voltage multiplier, source of direct current potential, a storage condenser, a load circuit, a plurality of condensers, a pair of magnetic switching devices having reed armatures adapted to vibrate between front and back contacts, and means for periodically vibrating said armatures at a predetermined rate, said devices being so arranged and connected that when the armatures of said devices are on their front contacts, a first one of said condensers will be connected to said source of potential and the second and third condensers will be connected in a series circuit including said storage condenser and load circuit in parallel, and when the armatures of said devices reverse their position said first condenser will be connected in series with said potential source and with said second and third condensers in parallel.

3. In a voltage multiplier, a source of direct current potential, a plurality of switching devices each comprising a pair of vibrating switches having front and back contacts, first, second and third condensers, a storage condenser, a load circuit, electromagnetic means for operating each of switching devices to open their back contacts and close their front contacts, means including a source of pulsating direct current adapted to alternately energize and deenergize said electromagnetic means to operate said switching devices at a predetermined rate, circuit means for connecting said first condenser to said source of potential when first one of said switching devices closes its front contacts, other circuit means including the back contact of both of said switching devices, for connecting said first condenser in series with said source and in parallel with said second and third condensers, and circuit means including the front contacts of said second switching device for connecting said second and third condensers in series with each other and with the storage condenser and load circuit in parallel.

4. In a voltage multiplier in combination, a source of direct current potential, a load circuit. a plurality of condensers including a storage condenser, a plurality of magnetic switching devices having mercury Wetted front and back contacts and a reed armature adapted to vibrate therebetween, means for periodically vibrating the armature of said devices at a predetermined rate, means for limiting the flow of current through said contacts during the initial making and final breaking period thereof, said means comprising inductance in series with said contacts and series resistance and capacity in shunt thereto, said contacts being so connected that when the arniatures of two of said devices close their respective front contacts a first one of said condensers will be connected to said source of potential and second and third condensers will be connected in a series circuit including said storage condenser and load circuit in parallel, and when said armatures reverse their positions and close their respective back contacts, said first condenser will be connected in series with said potential source and in parallel with said second and third condensers.

AUSTEN M. CURTIS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,992,908 Cockroft et a1. Feb. 26, 1935 2,239,786 Jones Apr. 29, 1941 2,267,233 Elstrom Dec. 23, 1941 

